In the dying days of the Celtic Tiger, Brendan Thornton did something that, at face value, seems utterly implausible: he profited handsomely from making a loss. Thornton was one of 231 high-income earners who signed up for a byzantine tax scheme that involved complex financial instruments and shell companies in the Caribbean. Thornton’s lawyers would later claim in court that the purpose of the scheme was to make a profit. However, it would subsequently transpire that Thornton, along with the other investors who backed 27 separate syndicates, would do far better when the scheme turned a loss instead.  Take Thornton,…